The results obtained from the available records of the 

 Nile River floods are given here for the first time, reduced 

 to a residual mass curve, and are of value in accordance 

 with the amount of reliability that can be placed on them. 

 Captain Lyons discusses the various Niloineters which have 

 been found, and the records obtained from them, in much 

 detail. The following are extracts from his report :— 



"The data available for a discussion of the Nile floods are not 

 inconsiderable but the greater part of them are, unfortunately, of 

 very unequal value, on account of the irregularity of the readings 

 at the Roda Nilometer at Cairo, and of the falsification of its 

 records, which is stated to have taken place in earlier times in 

 order to increase the revenue. They may be summarised as folio* s: 



(1) Readings of the Roda Nilometer from A.D. 700 to 1905, 



and since the Delta Barrage has been in use the low 

 stage readings have been affected by the artificially 

 raised water level. 



(2) Readings of the Nile gauge at the Delta Barrage from 



1846 to 1878. 



(3) Readings of the Nile gauge at Aswan from 1869 to the 



present time. 



(4) Readings of the Nile gauge at Wadi Haifa from January 



1890 to the present time. 



(5) Readings of the Khartoum Nile gauge from 1869 to 1883 



and from 1900 to the present time. 



" By using the Roda gauge from 182") to 1S72, and the Aswan 

 gauge readings from 1869 to 1902, and the Wadi Haifa gauge for 

 any subsequent years, we have a series of maximum readings of 

 the Nile flood for 80 years, which are very fairly accurate, since 

 for almost every year there was another gauge which was simul- 

 taneously recording the river levels. 



Period. Gauge. Verified by. 



1825-1845 Roda Barker, Holroyd, Bow ring, Curzon, etc. 



1846-1872 Roda Delta Barrage gauge. 



1869 - 1902 Aswan Roda Barrage and other gauges. 



1890 - 1904 Wadi Haifa Aswan, and many other gauges. 



